Certainly two different approaches, but both valid I think. They could be seen as compatible in a couple ways:

different approaches for different products: only some customers will tolerate being part of the QA process

different stages of the same product: you could do all the design first and then take a ‘release early, release often’ approach to development.

Although this last approach implies the dev team needs rapid feedback because sufficient cycles weren’t built into the design process. However, I could imagine a product that, even after a Cooper-style design stage, still needed to draw out tricky technology implementation issues.